As is well documented in the history of the development of semiconductor chips, the only thing that remains constant is change. It has always been common for a new generation of semiconductor chip to replace the old generation. Currently, in areas of memory storage and microprocessors, the rate of change has been accelerating. This acceleration of new generations of semiconductor chips has the effect of obsoleting entire systems of computers in a matter of just a few months. Because the old generation of systems are fully understood and appreciated by the user that effort to achieve such understanding is wasted by the introduction of the new generation of systems.
For example, over the past three years, since Intel (Intel is a registered trademark of Intel Corp.) released their 80386 microprocessor, users have only begun to understand and appreciate the powers and capacities of the 80386. However, within the last eighteen (18) months, Intel released a new microprocessor, the 80486, which is designed to work even faster and have more capacity than the 80386 generation microprocessors.
In effect this not only obsoletes the recently released 80386, but also entire computer systems around which that semiconductor chip is based. Thus, a consumer may have spent $3,000.00-$4,000.00 or more to purchase his computer only a few months before and now, with the release of the new semiconductor chip his entire machine has become obsolete. Since the 80486 is so much more powerful than 80386, it is not only conceivable, but even likely that important software programs will be written for 80486 which will not be able to function effectively with the 80386. These software programs may include such important packages as time and billing for companies, internal computer organization and backup and a myriad of other programs which may not only be desirable for the business person but in fact necessary for completion in our increasingly competitive world.
At first blush it would seem a simple problem to replace one semiconductor chip with another, given that they are designed to perform basically the same function and that they may even be from the same manufacturer. Using the example of the Intel 80386/486, which are both microprocessors made by the same company, it is readily seen why the problem of replacing the old generation semiconductor chip with the new is quite challenging
For example, the Intel 80386 microprocessor is a semiconductor chip manufactured in a pin grid array package having a 14 by 14 square array of electrical contact pins. As is well known, the center array of 8 by 8 pins is not installed so that there are 132 pins on the 80386 package. The Intel 80486 microprocessor is semiconductor chip manufactured in a pin grid array package having a 17 by .intg.square array of electrical contact pins. As is well known, the center array of 11 by 11 pins is not installed so that there are 168 pins on the 80486 package. Obviously, the 80486 can not simply plug into the slot provided for in the mother board of a computer designed to accept an 80386. Additionally, the electrical impulses read into and out of the 80386 will not be the same as the electrical impulses for the 80486. In fact, since the 80486 is a much more powerful semiconductor chip, there are eleven more power pins and twenty signal pins that are not present in the 80386. Accordingly, as will be typical with a new generation semiconductor chip, there are eleven more power pins and twenty signal pins that are not present in the 80386. Accordingly, additional semiconductor chip logical elements need to be added to the electrical impulses for the new generation semiconductor chip.
The new generation chip must be made to be compatible with the old generation mother board or like physical structure. The new generation chip must be able to read the electrical impulses of the old generation. The new generation chip must be able to output electrical impulses that are readable by the old generation mother board.
Additionally, in order to preserve the speed and other advantages of the new generation semiconductor chip, the electrical connection distances between the new semiconductor chip, the translating logic and the mother board must be kept to an absolute minimum. The electrical connection distance is important not only for purposes of speed, but also because long electrical connection lines encourage the connection lines to act as transmission line causing errors which may lead to a break down in the entire computer system.
Thus, a mechanical device which enables one semiconductor chip to replace another must meet the electrical limitations described herein. In addition to the electrical limitations, the mechanical device must also meet the physical limitation of the environment. In the case of the Intel 80386/486, the 486 is much larger physically and additional logical elements must be provided for translation of 386 input/output signals to 486 input/output signals and vice versa. Thus, initial attempts at mechanical adapters which included by laying the necessary elements in a side-by-side relationship failed, not only for electrical reasons, but also because, such an arrangement was physically incompatible with the tight physical environment of a microcomputer.
In solving this long felt need of saving equipment even after the essential semiconductor chip is out-moded and made obsolete by a new generation semiconductor chip, the mechanical translator in accordance with this invention utilizes a piggy back mounting system which minimizes electrical connection distances and gives the mechanical translator a low profile.